In conventional photography, the camera must typically be focused at the time the photograph is taken. The resulting image may have only color data for each pixel; accordingly, any object that was not in focus when the photograph was taken cannot be brought into sharper focus because the necessary data does not reside in the image.
By contrast, light field images typically encode additional data for each pixel related to the trajectory of light rays incident to that pixel when the light field image was taken. This data can be used to manipulate the light field image through the use of a wide variety of rendering techniques that are not possible to perform with a conventional photograph. In some implementations, a light field image may be refocused and/or altered to simulate a change in the center of perspective (CoP) of the camera that received the image.
As part of such rendering, or as a subsequent step, it may be useful to blur the light field image, or a portion of the light field image. Blurring may entail mixing the color value of a pixel with those of surrounding pixels to make an object appear less clear. In order for blur in a light field image to be convincing, the depth of objects may need to be taken into account. For example, objects closer to the focus depth of the light field image may receive less blurring, while those further from the focus depth may receive more blurring. Thus, if applied to light field images, traditional naive blurring techniques may display noticeable inaccuracies.
Raytracing techniques, which process objects in the light field image based on depth, may provide greater accuracy by properly taking into account object depth and/or occlusion, but may also require significant computational power in order to do so. Hence, such techniques may be time consuming and may not be usable for real time manipulation of the light field image. Accordingly, it would be advantageous to provide blurring systems and methods for light field images that overcome the drawbacks of conventional techniques.